Endoscopic snare device

ABSTRACT

The present subject matter discloses a tissue removal tool for use with an endoscope. The tool comprises a loop formed by a piece of wire and movable between an open position and a closed position, and a transmitting assembly comprising: a handle; and a link having a first end attached to the handle and a second end attached to the loop, the loop portion being movable between the open and closed position by action of the handle. The loop is defined in the open position by a proximal portion and a distal portion. The widest portion of the loop is more proximal to a proximal end of the loop than the mid-point of the length of the loop is.

CROSS-REFERENCES

This application is a continuation of U.S. patent application Ser. No.15/866,401, filed Jan. 9, 2018, which claims the benefit of U.S.Provisional Patent Application No. 62/444,144, filed on Jan. 9, 2017,both disclosures of which are hereby incorporated herein by reference intheir entirety.

TECHNICAL FIELD

The present subject matter relates generally to endoscopic snaredevices.

BACKGROUND

Polypectomy, or the removal of polyps, has become one of the most commonendoscopic procedures in gastrointestinal endoscopy today. Its relativesimplicity often belies the effectiveness of the procedure at preventingcolorectal cancer. The National Polyp Study (NPS) demonstrated areduction in the incidence of colorectal cancer of 76%-90% followingcolonoscopic polypectomy. Standard practice for polypectomy has been touse an electrocautery or “hot” snare to remove polyps due to the factthat it reduces the risk of bleeding as a result of the coagulationeffect created by the current. Electrocautery, however, can createinadvertent damage to healthy tissue and may not be necessary forsmaller sized polyps where bleeding risk is not a concern.

A “cold” snare, such as US Endoscopy Group Inc.'s Exacto® snare, isdesigned for polypectomy procedures where diminutive polyps areencountered. It enables a clean cut that reduces polyp “fly away” formthe resection site. Studies comparing Exacto® snare to hot snares haveshown that, for diminutive polyps in the 3-8 mm range, there is nodifference in postpolypectomy bleeding and it requires less time to usethan hot snares while being just as safe and effective.

SUMMARY

The present subject matter describes a tissue removal tool for use withan endoscope. The tool comprises a loop formed by a piece of wire andmovable between an open position and a closed position, and atransmitting assembly comprising: a handle; and a link having a firstend attached to the handle and a second end attached to the loop, theloop portion being movable between the open and closed position byaction of the handle. The loop is defined in the open position by aproximal portion and a distal portion. The widest portion of the loop ismore proximal to a proximal end of the loop than the mid-point of thelength of the loop is.

The present subject matter further describes a tissue removal toolhaving a cutting section disposed along the distal portion of the loop.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the general inventive concepts willbecome apparent from the following detailed description made withreference to the accompanying drawings.

FIG. 1 is a perspective view of a retrieval device, showing a snare inan open position;

FIG. 2 is an enlarged sectional view of a portion of the retrievaldevice of FIG. 1 , showing the snare in a closed position within aconduit;

FIG. 3 is an embodiment of the loop with a general cable form design;

FIG. 4 is an embodiment of the loop with a general monofilament formdesign;

FIG. 5 is a first embodiment of the loop with a distal cutting sectionand a proximal portion formed from separate wires;

FIGS. 6 a-6 b show a second embodiment of the loop with microtomes orcutting elements;

FIG. 7 is a third embodiment of the loop with a torsion tip; and

FIGS. 8 a-8 c show a fourth embodiment of the loop with separate loopelements;

FIGS. 9 a-9 b show a fifth embodiment of the loop with a tapered orground portion;

FIG. 10 is a sixth embodiment of the loop with a coined proximalportion;

FIG. 11 is a seventh embodiment of the loop with a coined or non-coinedproximal portion and a coined distal portion;

FIGS. 12 a-12 b show an eighth embodiment of the loop with a pluralityof coined sections;

FIG. 13 is a ninth embodiment of the loop showing a method for mountingcutting elements; and

FIG. 14 is another embodiment of the loop detailing the loop.

DETAILED DESCRIPTION OF INVENTION

This Detailed Description merely describes exemplary embodiments inaccordance with the general inventive concepts and is not intended tolimit the scope of the invention or the claims in any way. Indeed, theinvention as described by the claims is broader than and unlimited bythe exemplary embodiments set forth herein, and the terms used in theclaims have their full ordinary meaning.

The general inventive concepts will now be described with occasionalreference to the exemplary embodiments of the invention. This generalinventive concept may, however, be embodied in different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure will bethorough and complete, and will fully convey the scope of the generalinventive concepts to those skilled in the art.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art encompassing the general inventive concepts. The terminology setforth in this detailed description is for describing particularembodiments only and is not intended to be limiting of the generalinventive concepts. As used in this detailed description and theappended claims, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

Unless otherwise indicated, all numbers such as, for example, numbersexpressing measurements or physical characteristics, used in thespecification and claims are to be understood as being modified in allinstances by the term “about.” Accordingly, unless otherwise indicated,the numerical properties set forth in the specification and claims areapproximations that may vary depending on the suitable properties soughtto be obtained in embodiments of the invention. Notwithstanding that thenumerical ranges and parameters setting forth the broad scope of thegeneral inventive concepts are approximations, the numerical values setforth in the specific examples are reported as precisely as possible.Any numerical values, however, inherently contain certain errorsnecessarily resulting from error found in their respective measurements.

The present application describes a tissue removal tool for use with anendoscope, comprising: a loop formed by a piece of wire and movablebetween an open position and a closed position; a handle; and a linkhaving a first end attached to the handle and a second end attached tothe loop, the loop being movable between the open and closed position byaction of the handle, wherein the loop is defined in the open positionby a proximal portion and a distal portion.

Referring to FIG. 1 , the exemplary tool 10 includes a loop 12 formed bya piece of wire 14. A wire of any suitable material may be used to formthe loop, such as for example, a metal, such as stainless steel,nitinol, plastic or carbon nanotube, glass fiber, or hybrid technology.The loop may also be formed by a monofilament or a cable. The variationsin the wire shape and orientation along the length of the wire may bemade by mechanically bending or twisting a preformed wire into thedesired shape and orientation, or the wire may be originallymanufactured to have the desired shape and orientation, such as forexample, a preformed plastic piece. A suitable material will be flexibleand have memory to allow deployment and retrieval of the loop. The wireforms a plurality of segments separated by collapse-resistant bends todefine a loop opening. The loop is movable between an open position, ordeployed position, and a closed position, or retrieved position. Theloop 12 is illustrated in an open position in FIG. 1 . The loop ispolygon-shaped and, specifically, the loop is generally diamond-shaped.In FIG. 2 , the loop 12 is shown in a closed position within a distalportion of the tool 10. As discussed herein, the loop 12 is within aconduit 18. In this closed or retrieved position, the exemplary loop hasa length L₁.

The tool may include a support assembly and a transmitting system formoving the loop between an open position and a closed position. In theexemplary tool 10 illustrated in FIG. 1 , the support assembly includesa base or body 16 and an elongated hollow tube, tubular member orconduit 18. The transmitting assembly includes a handle 20 movablerelative to the body 16 and a link 22. One end of the link is fixed tothe handle and a second end is remote from the body. As shown in FIGS. 1and 2 , the link 22 extends substantially through a length of theconduit 18. The conduit 18 may be any suitable, small-diameter tubeformed of a low-friction flexible material such as, for example,polytetrafluorethylene, high density polyethylene, polyether blockamide, or other comparable materials. The conduit 18 defines a lumenwith an opening at a distal second end 28, as best seen in FIG. 2 whichshows a cross-sectional view of a distal portion of the tool 10. Aproximal first end 30 of the conduit is fixed to the body 16.

The handle allows an operator to move the loop back and forth between adeployed position, as shown in FIG. 1 , and a closed position, as shownin FIG. 2 . Referring again to FIG. 1 , the body 16 includes a fixedring 24 at a proximal end. The handle 20 may be slid by an operatorrelative to the body 16 by use of the handle 20 and, specifically, byuse of one or both of two rings 26 a, 26 b. The handle 20 is mountedover an elongated section of the body 16 and is movable relative to thebody in the direction D₁ to deploy the loop 12, or in an opposingdirection D₂ to close the loop 12. For example, an operator may place afinger in each of the rings 26 a, 26 b and a thumb of the same hand inthe body ring 24. By moving the two fingers in the direction D₁, anoperator can move the handle 20 relative to the body 16. This movementof the handle will deploy the loop. In contrast, the handle 20 can beslid in the opposite direction D₂ by pulling one's fingers towards one'sthumb to close the loop.

A link 22 is connected to the handle 20 for transferring axial motionfrom the handle 20 to other parts of the device. The link may beconstructed of any suitable rigid material, and may be solid, hollow, orany suitable elongated object or combination of objects. The link may beone piece or formed from a series of pieces and connections, such as forexample, hypodermic tubes, swage connections, and cables. The link 22has a first end fixed to the handle 20 and a second end remote from thebody 16. As shown in the drawings, the link extends substantiallythrough the conduit 18.

FIG. 3 shows a general form for a cable cold cutting snare loop. FIG. 4shows a general form for a monofilament cold cutting snare loop. Theloops 12 comprise a distal portion 120 and a proximal portion 130. Theloop comprises a cutting section 140 along the distal portion 120 of theloop 12. The cutting section 140 covers roughly ⅓ to ½ of the loop 12,and may be continuous or discrete. In some embodiments, the cuttingsection 140 extends about 1-5 mm out from the distal end 150 in eitherdirection. In some embodiments, the cutting section 140 extends about 5mm to 15 mm out from the distal end 150 in either direction. In someembodiments, the cutting section 140 extends about 10 mm out from thedistal end 150 in both directions. In some embodiments, the cuttingsection 140 extends about 5 mm to 15 mm out from the distal end 150 inboth directions. The cutting section 140 needs to be thin enough toprovide cutting pressure to tissue. The cutting section 140 comprises adiameter of 0.36 mm or thinner so as to enable cold cutting of tissue.In some embodiments, the diameter is 0.30 or thinner. The cutting mostlyoccurs on the distal portion 120 of the snare by virtue of tensilemechanics of the snare as it is retracted into the tubular member 18.The distal tip 150 may also be optimized to dissipate stress uniformlyso as not to deform during retraction.

The proximal portion 130 of the loop 12 generally does not performcutting but provides assistance and support to encircle and recruittissue for cutting. Increasing the stiffness of the proximal portionallows for greater indentation of the tissue which improves tissuerecruitment. The stiffer proximal portion 130 can be about the proximal⅓ to ½ of the loop 12. The proximal portion may vary in stiffness alongits length.

In an embodiment shown as FIG. 5 , the proximal portion 130 comprisesflat wire or coined cable. The cutting section 140 generally comprisesthinner wire than the proximal portion 130. These separate portions maybe joined together by welding, gluing, crimping, swaging, soldering, orother techniques familiar to those skilled in the art.

In an embodiment shown as FIGS. 6 a and 6 b , the cutting section 140comprises cutting blades disposed on an otherwise non-cutting snarewire.

In an embodiment shown as FIG. 7 , the loop 12 is a solid rectangularwire filament loop with a torsion tip 150 to preserve its shape.

In some embodiments, such as those shown as FIGS. 8 a-8 c , the loop 12comprises an inner loop 170 (i.e., cutting section) and an outer loop160. The inner loop 170 is bonded (i.e., welded or other known suitablebonding methods) to the outside loop 160 in at least one location. Theinner loop 170 comprises a thinner wire that is configured to be moreeffective for cold cutting. The outer loop 160 is thicker and stifferthan the inner loop 170. The outer loop 160 allows the loop 12 to indentand recruit tissue. In some embodiments, the inner loop 170 only coversthe distal/mid portion of the loop 12, since that is where the cuttingtruly occurs. In some embodiments, the inner loop 170 is a full loop,since this may make fixturing/manufacture more efficient. In someembodiments, the inner loop 170 has a round cross-section. In someembodiments, the inner loop 170 is a flat or square wire.

In an embodiment shown in FIGS. 9 a and 9 b , the loop 12 comprisestapered or ground wire. The proximal portion 130 is thicker than thedistal portion 120. The tool may further comprise mechanisms forpromoting positioning of the loop 12 within the body, such as arotatable link 22. In some embodiments, the link 22 is of sufficientlyless torsional rigidity than the legs of the loop 12.

In an embodiment shown in FIG. 10 , the loop 12 comprises cable ormonofilament loop with a coined proximal portion 130 and non-coineddistal portion 120.

In an embodiment shown in FIG. 11 , the loop 12 comprises a cable ormonofilament loop with a coined distal portion 120, which creates asharp inner edge to provide for cutting action. In some embodiments, theproximal portion may also be coined in a perpendicular plane to thedistal coined portion.

In some embodiments shown in FIGS. 12 a and 12 b , the loop 12 comprisescoined at various locations 180 so as to be advantageous for cutting orgrasping tissue. It may be several small level and cross-sectionalchanges, a few longer sections and may be either symmetrical orasymmetrical with respect to the loop centerlines (vertical andhorizontal).

In an embodiment shown in FIG. 13 , the cutting section comprises acutting element 190 with eyelets 200. The eyelets 200 could have thewire slid through and then crimped, welded, glued or otherwise bonded inplace. The eyelets 200 could be any opening shape, such as round orsquare.

Referring now to FIG. 4 , in the exemplary loop 12, the wire is bent atthe distal tip 150 to form a torsion tip, or a nearly 360° circular tip.The tip allows for dissipation of stress through the snare, somethingthat is of particular importance when cold snaring because of therelatively larger forces used compared to hot snaring. One feature tohelp to facilitate this is to use multifilament cable. The strands inthe cable move relative to one another and allow for stresses to be moreevenly spread across the snare body. To achieve the same effect inmonofilament wire, one can create a loop that mimics a standard torsionspring without increasing the cutting thickness of the tip. Because thetip is a loop and not a simple bend, stress is distributed more evenlyaround the entire circumference upon closing, minimizing plasticdeformation.

The distal tip 150 of the tool may have alternative shapes. US2014/0052142 A1 and US2015/0066045 A1 disclose multiple distal loop orcoil tip designs, the contents of which are incorporated herein. Thewire may form a torsion tip with a 180° bend. In another distal tip, thewire within the 180° bend may be in a landscape orientation. In anotherexemplary distal tip, the loop is formed by a wire having two portions.The two wire portions form an atraumatic tip at a distal most point. Asassembled, the wire portions function as a loop in the same way asdiscussed herein.

Another aspect of the present subject matter is to provide a new shapeof the loop. Referring to FIG. 14 , in some embodiments, the loop 152comprises a widest portion 166 and a length L measured between aproximal end and a distal end. The proximal end is defined where theloop begins to close during retraction into the tubular member,irrespective of where the loop connection physically may occur. Thedistal end is defined by the most distal end, or ends, of the loop 152.In any instance where there are proximal legs that are excessively long,and/or the distal tip is inverted or of any other unusual geometry, themidpoint shall be considered only with respect to the broad portions ofthe form, which is defined between the proximal end and the distalend(s). The widest portion 166 of the loop 152 is more proximal to thetubular member 18 than the mid-point of the length L of the loop 152 is.In other words, the widest portion 166 is closer to the tubular member18 than the mid-point of the length L of the loop 152, such that theloop 152 is easier to be controlled during the procedures. In someembodiments, the distance D from the mid-point of the length L of theloop 152 to the widest portion 166 of the loop 152 is about 3%-45% ofthe length L. In some embodiments, the distance D from the mid-point ofthe length L of the loop 152 to the widest portion 166 of the loop 152is about 10%-35% of the length L. In some embodiments, the distance Dfrom the mid-point of the length L of the loop 152 to the widest portion166 of the loop 152 is about 12%-25% of the length L.

It should be understood that some or all of the features described abovemay be applied to any suitable endoscopic devices or combination ofendoscopic devices, such as snare-needle device, a multistage snare, oran endoscopic retrieval device.

A person skilled in the art should understand that although theabove-described snare features are designed for cold cutting, they mayalso be utilized with electrocautery without compromising the featuresthat make them useful for gathering and cutting tissue.

A person skilled in the art should understand that the endoscopic devicedescribed in the present subject matter is not necessary to comprise thesupport assembly (including the base and the elongated tubular member)and/or the transmitting assembly (including the handle and the link). Ahandle may be formed by or connected to the proximal end of the loop.

While various inventive aspects, concepts and features of the generalinventive concepts are described and illustrated herein in the contextof various exemplary embodiments, these various aspects, concepts andfeatures may be used in many alternative embodiments, eitherindividually or in various combinations and sub-combinations thereof.Unless expressly excluded herein all such combinations andsub-combinations are intended to be within the scope of the generalinventive concepts. Still further, while various alternative embodimentsas to the various aspects, concepts and features of the inventions (suchas alternative materials, structures, configurations, methods, circuits,devices and components, alternatives as to form, fit and function, andso on) may be described herein, such descriptions are not intended to bea complete or exhaustive list of available alternative embodiments,whether presently known or later developed. Those skilled in the art mayreadily adopt one or more of the inventive aspects, concepts or featuresinto additional embodiments and uses within the scope of the generalinventive concepts even if such embodiments are not expressly disclosedherein. Additionally, even though some features, concepts or aspects ofthe inventions may be described herein as being a preferred arrangementor method, such description is not intended to suggest that such featureis required or necessary unless expressly so stated. Still further,exemplary or representative values and ranges may be included to assistin understanding the present disclosure; however, such values and rangesare not to be construed in a limiting sense and are intended to becritical values or ranges only if so expressly stated. Moreover, whilevarious aspects, features and concepts may be expressly identifiedherein as being inventive or forming part of an invention, suchidentification is not intended to be exclusive, but rather there may beinventive aspects, concepts and features that are fully described hereinwithout being expressly identified as such or as part of a specificinvention. Descriptions of exemplary methods or processes are notlimited to inclusion of all steps as being required in all cases, nor isthe order that the steps are presented to be construed as required ornecessary unless expressly so stated.

We claim:
 1. A tissue removal tool for use with an endoscope,comprising: a loop formed by a piece of wire and movable between an openposition and a closed position, wherein the loop is defined in the openposition by a proximal portion and a distal portion, and whereinportions of the loop are coined; a cutting section disposed at least atthe distal portion of the loop, wherein the cutting section comprisesthinner wire than the proximal portion of the loop; a transmittingassembly comprising: a handle; and a link having a first end attached tothe handle and a second end attached to the loop, the loop portion beingmovable between the open and closed position by action of the handle. 2.The tissue removal tool of claim 1, wherein both the distal portion andthe proximal portion of the loop are coined.
 3. The tissue removal toolof claim 2, wherein the proximal portion of the loop is coined in aperpendicular plane to the distal coined portion.
 4. The tissue removaltool of claim 1, wherein the wire is bent at a distal end of the distalportion to form a torsion tip.
 5. The tissue removal tool of claim 1,wherein the loop is a monofilament loop.
 6. The tissue removal tool ofclaim 1, wherein a widest portion of the loop is more proximal to aproximal end of the loop than a mid-point of the length of the loop is.7. The tissue removal tool of claim 6, wherein a distance from amid-point of the length of the loop to the widest portion of the loop isabout 3%-45% of the length.
 8. The tissue removal tool of claim 7,wherein a distance from the mid-point of the length of the loop to thewidest portion of the loop is about 10%-35% of the length.
 9. The tissueremoval tool of claim 8, wherein the distance from the mid-point of thelength of the loop to the widest portion of the loop is about 12%-25% ofthe length.
 10. The tissue removal tool of claim 1 further comprising: asupport assembly comprising a base and an elongated tubular member,wherein the handle is movable relative to the base, and the link extendsthrough at least a portion of the tubular member.
 11. The tissue removaltool of claim 1, wherein the cutting section covers about ⅓ to ½ of theloop at the distal portion of the loop.
 12. The tissue removal tool ofclaim 1, wherein the cutting section extends about 5 mm to 15 mm from adistal end of the loop in either direction.
 13. The tissue removal toolof claim 12, wherein the cutting section extends about 10 mm from adistal end of the loop in either direction.
 14. The tissue removal toolof claim 1, wherein the cutting section comprises a diameter of 0.36 mmor thinner.
 15. The tissue removal tool of claim 1, wherein the coinedportions of the loop are either symmetrical or asymmetrical with respectto the loop centerlines.
 16. A tissue removal tool for use with anendoscope, comprising: a loop formed by a piece of wire and movablebetween an open position and a closed position, wherein the loop isdefined in the open position by a proximal portion and a distal portion,and wherein portions of the loop are coined; a cutting section disposedat least at the distal portion of the loop, wherein the cutting sectioncomprises thinner wire than the proximal portion of the loop; atransmitting assembly comprising: a handle; and a link having a firstend attached to the handle and a second end attached to the loop, theloop portion being movable between the open and closed position byaction of the handle; and wherein the cutting section is a cuttingelement comprising cutting blades disposed on an otherwise non-cuttingsnare wire.
 17. The tissue removal tool of claim 16 further comprising:a support assembly comprising a base and an elongated tubular member,wherein the handle is movable relative to the base, and the link extendsthrough at least a portion of the tubular member.
 18. The tissue removaltool of claim 16, wherein both the distal portion and the proximalportion of the loop are coined.
 19. The tissue removal tool of claim 16,wherein the proximal portion of the loop is coined in a perpendicularplane to the distal coined portion.
 20. The tissue removal tool of claim16, wherein the wire is bent at a distal end of the distal portion toform a torsion tip.
 21. The tissue removal tool of claim 16, wherein theloop is a monofilament loop.
 22. The tissue removal tool of claim 16,wherein the cutting section covers about ⅓ to ½ of the loop at thedistal portion of the loop.
 23. The tissue removal tool of claim 16,wherein the cutting section extends about 5 mm to 15 mm from a distalend of the loop in either direction.
 24. The tissue removal tool ofclaim 23, wherein the cutting section extends about 10 mm from a distalend of the loop in either direction.
 25. The tissue removal tool ofclaim 16, wherein the cutting section comprises a diameter of 0.36 mm orthinner.
 26. The tissue removal tool of claim 16, wherein the coinedportions of the loop are either symmetrical or asymmetrical with respectto the loop centerlines.
 27. A tissue removal tool for use with anendoscope, comprising: a loop formed by a piece of wire and movablebetween an open position and a closed position, wherein the loop isdefined in the open position by a proximal portion and a distal portion,and wherein portions of the loop are coined; a cutting section disposedat least at the distal portion of the loop, wherein the cutting sectioncomprises thinner wire than the proximal portion of the loop; atransmitting assembly comprising: a handle; and a link having a firstend attached to the handle and a second end attached to the loop, theloop portion being movable between the open and closed position byaction of the handle; and wherein the loop comprises an inner loop andan outer loop, wherein the inner loop is secured to the outer loop in atleast one location, and the inner loop is thinner than the outer loop.28. The tissue removal tool of claim 27, wherein the inner loop onlycovers the distal portion of the loop.
 29. The tissue removal tool ofclaim 27, wherein the inner loop substantially covers the whole loop.30. The tissue removal tool of claim 27 further comprising: a supportassembly comprising a base and an elongated tubular member, wherein thehandle is movable relative to the base, and the link extends through atleast a portion of the tubular member.
 31. The tissue removal tool ofclaim 27, wherein both the distal portion and the proximal portion ofthe loop are coined.
 32. The tissue removal tool of claim 27, whereinthe proximal portion of the loop is coined in a perpendicular plane tothe distal coined portion.
 33. The tissue removal tool of claim 27,wherein the wire is bent at a distal end of the distal portion to form atorsion tip.
 34. The tissue removal tool of claim 27, wherein the loopis a monofilament loop.
 35. The tissue removal tool of claim 27, whereinthe cutting section covers about ⅓ to ½ of the loop at the distalportion of the loop.
 36. The tissue removal tool of claim 27, whereinthe cutting section extends about 5 mm to 15 mm from a distal end of theloop in either direction.
 37. The tissue removal tool of claim 36,wherein the cutting section extends about 10 mm from a distal end of theloop in either direction.
 38. The tissue removal tool of claim 27,wherein the cutting section comprises a diameter of 0.36 mm or thinner.39. The tissue removal tool of claim 27, wherein the coined portions ofthe loop are either symmetrical or asymmetrical with respect to the loopcenterlines.